Don't teleport entities that are considered dead. Addresses BUKKIT-1331

Teleportation should never be processed on dead entities. If you wish
to teleport an entity, do it on a living entity. If you wish to
teleport a player, set their respawn location in PlayerRespawnEvent.

src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java

@@ -190,6 +190,10 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
     }
 
     public boolean teleport(Location location, TeleportCause cause) {
+        if (entity.vehicle != null || entity.passenger != null || entity.dead) {
+            return false;
+        }
+
         entity.world = ((CraftWorld) location.getWorld()).getHandle();
         entity.setLocation(location.getX(), location.getY(), location.getZ(), location.getYaw(), location.getPitch());
         // entity.setLocation() throws no event, and so cannot be cancelled

src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java

@@ -41,6 +41,7 @@ import org.bukkit.entity.Projectile;
 import org.bukkit.entity.SmallFireball;
 import org.bukkit.entity.Snowball;
 import org.bukkit.entity.WitherSkull;
+import org.bukkit.event.player.PlayerTeleportEvent;
 import org.bukkit.inventory.EntityEquipment;
 import org.bukkit.potion.PotionEffect;
 import org.bukkit.potion.PotionEffectType;
@@ -346,4 +347,13 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
     public boolean getCanPickupItems() {
         return getHandle().canPickUpLoot;
     }
+
+    @Override
+    public boolean teleport(Location location, PlayerTeleportEvent.TeleportCause cause) {
+        if (getHealth() == 0) {
+            return false;
+        }
+
+        return super.teleport(location, cause);
+    }
 }

src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java

@@ -348,6 +348,10 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
     public boolean teleport(Location location, PlayerTeleportEvent.TeleportCause cause) {
         EntityPlayer entity = getHandle();
 
+        if (getHealth() == 0 || entity.dead) {
+            return false;
+        }
+
         if (entity.playerConnection == null || entity.playerConnection.disconnected) {
             return false;
         }